Polldoo, from the Irish poll dubh, meaning "black hole" or "dark pit", is the kind of toponym that tends to attach itself to places with something genuinely unusual about them, whether a swallowhole in limestone karst, a deep boggy hollow, or a feature in the landscape that resisted easy explanation to those who first named it. The townland of Derryfrench, where this site sits in County Galway, takes its own name from the Irish doire, an oak wood, and the surname French, one of the fourteen tribes of Galway whose landholdings spread widely across the county from the medieval period onward.

Beyond those threads of etymology and geography, the specific character of this particular Polldoo remains thinly documented in what is publicly available at present. The site carries a monument record, which places it in the company of archaeological features considered significant enough to log and protect, but the details that would explain what it actually is, its form, its age, any finds or investigations associated with it, have not yet made their way into accessible records. That gap is not unusual for rural Connacht, where the density of archaeological sites often outpaces the resources available to fully document them. Galway's landscape is threaded with souterrains, ring-forts, holy wells, and natural features that were worked into the lives and beliefs of successive communities, and a name like Polldoo suggests this place held some significance, practical or otherwise, for the people who lived nearby.